# HG changeset patch
# User Laman
# Date 2021-10-14 18:07:25
# Node ID 6644c5267fb5f805588463da43fb9d15e4386a51
# Parent  d908ea134adb7ee3c081d7537f843bff7e751570

added tests

diff --git a/.hgignore b/.hgignore
--- a/.hgignore
+++ b/.hgignore
@@ -1,1 +1,2 @@
 .idea/
+__pycache__/
diff --git a/rank_progress.py b/rank_progress.py
--- a/rank_progress.py
+++ b/rank_progress.py
@@ -36,6 +36,7 @@ class Record:
 
 class RankTracker:
 	def __init__(self, rating):
+		assert rating >= -900
 		self._rounded_rating = round_rating(rating)
 
 	@property
@@ -43,22 +44,24 @@ class RankTracker:
 		return rating_to_rank(self._rounded_rating)
 
 	def update(self, rating):
+		assert rating >= -900
 		rounded_rating = round_rating(rating)
+		old_rank = self.rank
 
 		if rounded_rating == self._rounded_rating:
-			return False
+			pass
 		elif rounded_rating > self._rounded_rating:  # promotion
 			self._rounded_rating = rounded_rating
-			return self.rank
 		else:  # demotion
-			if rounded_rating >= 1500 and self._rounded_rating - rating > 100:
+			if self._rounded_rating >= 1600 and self._rounded_rating - rating > 100:
 				self._rounded_rating = rounded_rating
-				return self.rank
 			elif self._rounded_rating - rating > 150:
 				self._rounded_rating = rounded_rating+100
-				return self.rank
 			else:
-				return False
+				pass
+
+		new_rank = self.rank
+		return new_rank if new_rank != old_rank else False
 
 
 def parse_record(record):
diff --git a/test.py b/test.py
new file mode 100644
--- /dev/null
+++ b/test.py
@@ -0,0 +1,54 @@
+from unittest import TestCase
+
+from rank_progress import RankTracker
+
+
+class TestRankTracker(TestCase):
+	def test_no_change(self):
+		t = RankTracker(1945)  # 2k
+		for r in [1945, 1949, 1900, 1850]:
+			self.assertFalse(t.update(r), r)
+
+	def test_promotion(self):
+		# basic
+		t = RankTracker(1945)
+		for (rating, rank) in [(1950, "1k"), (1945, False), (2000, False), (2049, False), (2051, "1d")]:
+			self.assertEqual(t.update(rating), rank, (rating, rank))
+
+		# 2+ ranks leaps
+
+		# limited when pushing the personal best
+		self.skipTest("not yet implemented")
+		t = RankTracker(1100)
+		self.assertEqual(t.update(1299), "9k")
+		self.assertEqual(t.update(1250), "8k")
+		self.assertEqual(t.update(1500), "6k")
+
+		# regular below the personal best
+		t = RankTracker(1201)  # 9k
+		t.update(1000)
+		t.update(900)
+		t.update(849)  # 11k
+		self.assertEqual(t.update(1250), "8k")
+
+	def test_demotion(self):
+		t = RankTracker(2069)
+		self.assertEqual(t.update(1995), "1k")
+
+		t = RankTracker(1590)
+		self.assertEqual(t.update(1387), "7k")
+
+		t = RankTracker(1087)
+		self.assertFalse(t.update(995))
+		self.assertEqual(t.update(940), "11k")
+
+	def test_edges_cases(self):
+		t = RankTracker(-900)
+		self.assertEqual(t.rank, "30k")
+		with self.assertRaises(AssertionError):
+			t.update(-901)
+
+		t = RankTracker(2700)
+		self.assertEqual(t.rank, "7d")
+		self.assertFalse(t.update(2750))
+		self.assertFalse(t.update(2800))